Immunology is a branch of medical sciences that is concerned with the study of the immune system. It is a system that protects the body from several infections through various lines of defense. Defects in the immune system can cause various diseases such as allergy, autoimmunity and cancer. The immune system is composed of structures and processes that have evolved to protect the body from diseases. There are two types of immunity, namely, innate immunity and adaptive immunity. Innate immunity is non-specific and the responses are same for all potential pathogens. It is the first line of defense. Adaptive immunity builds up memory of encountered infections to generate enhanced response specific to a foreign substance. Most of the topics introduced in this book cover new applications of immunology. It studies, analyses and upholds the pillars of this field and its utmost significance in modern times. The topics covered in this book offer the readers new insights in the field of immunology.